Commit b33fff07 authored by Sami Tolvanen's avatar Sami Tolvanen Committed by Kees Cook
Browse files

x86, build: allow LTO to be selected 



Pass code model and stack alignment to the linker as these are not
stored in LLVM bitcode, and allow CONFIG_LTO_CLANG* to be enabled.

Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
parent d2dcd3e3

arch/x86/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -95,6 +95,8 @@ config X86 
	select ARCH_SUPPORTS_DEBUG_PAGEALLOC

	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64

	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096

	select ARCH_SUPPORTS_LTO_CLANG		if X86_64

	select ARCH_SUPPORTS_LTO_CLANG_THIN	if X86_64

	select ARCH_USE_BUILTIN_BSWAP

	select ARCH_USE_QUEUED_RWLOCKS

	select ARCH_USE_QUEUED_SPINLOCKS

arch/x86/Makefile

+5 −0
Original line number Diff line number Diff line
@@ -166,6 +166,11 @@ ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 
	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)

endif



ifdef CONFIG_LTO_CLANG

KBUILD_LDFLAGS	+= -plugin-opt=-code-model=kernel \

		   -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)

endif



# Workaround for a gcc prelease that unfortunately was shipped in a suse release

KBUILD_CFLAGS += -Wno-sign-compare

#